Pool Boiling of Low-GWP Replacements for R134a on a Reentrant Cavity Surface

This paper quantifies the pool boiling performance of R134a, R1234yf, R513A, and R450A on a flattened, horizontal reentrant cavity surface. The study showed that the boiling performance of R134a on the Turbo-ESP exceeded that of the replacement refrigerants for heat fluxes greater than 20 kWm^-2. On average, the heat flux for R1234yf and R513A was 16 % and 19 % less than that for R134a, respectively, for R134a heat fluxes between 20 kWm^-2 and 110 kWm^-2. The heat flux for R450A was on average 57 % less than that of R134a for heat fluxes between 30 kWm^-2 and 110 kWm^-2. A model was developed to predict both single-component and multi-component pool boiling of the test refrigerants on the Turbo-ESP surface. The model accounts for viscosity effects on bubble population and uses the Fritz (1935) equation to account for increased vapor production with increasing superheat. Both loss of available superheat and mass transfer resistance effects were modeled for the refrigerant mixtures. For most heat fluxes, the model predicted the measured superheat to within ± 0.31 K.

Horizontal convective boiling of R1234yf, R134a, and R450A within a micro-fin tube

This paper presents local convective boiling heat transfer and Fanning friction factor measurements in a micro-fin tube for R134a and two possible low global warming potential (GWP) refrigerant replacements for R134a, namely R1234yf and R450A. Test section heating was achieved with water in either counterflow or in parallel flow with the test refrigerant to provide for a range of heat fluxes for each thermodynamic quality. An existing correlation from the literature for single and multi-component mixtures was shown to not satisfactorily predict the convective boiling measurements for flow qualities greater than 40%. Accordingly, a new correlation was developed specifically for the test fluids of this study so that a fair comparison of the heat transfer performance of the low GWP refrigerants to that of R134a could be made. The new correlation was used to compare the heat transfer coefficient of the three test fluids at the same heat flux, saturated refrigerant temperature, and refrigerant mass flux. The resulting example comparison, for the same operating conditions, showed that the heat transfer coefficient of the multi-component R450A and the single-component R1234yf were, on average, 15% less and 5% less, respectively, than that of the single-component R134a. Friction factor measurements were also compared to predictions from an existing correlation. A new correlation for the friction factor was developed to provide a more accurate prediction. The measurements and the new models are important for the evaluation of potential low-GWP refrigerants replacements for R134a.

Tests of the SIBYLL 2.3 high-energy hadronic interaction model using the KASCADE-Grande muon data

The KASCADE-Grande observatory was a ground-based air shower array dedicated to study the energy and composition of cosmic rays in the energy interval E = 1 PeV –1 EeV. The experiment consisted of different detector systems which allowed the simultaneous measurement of distinct components of air showers (EAS), such as the muon content. In this contribution, we study the total muon number and the lateral density distribution of muons in EAS detected by KASCADE-Grande as a function of the zenith angle and the total number of charged particles. The attenuation length of the muon content of EAS is also measured. The results are compared with the predictions of the SIBYLL 2.3 high-energy hadronic interaction model.

Abstract P6-09-50: Impact of young age on recurrence and mortality after surgery in breast cancer: 15 years active surveillance

Introduction:Substantial efforts have been made to find factors associated with breast cancer (BC) recurrence and mortality after BC treatment. So far TNM stage, ER, PR, and HER2 status are considered as the major predictive markers of BC recurrence and used for treatment decision. However, most of these factors were evaluated independent from other important confounders such as age, stage, and various anti-cancer treatments because they were mostly derived from clinical trials. In Korea, up to 50% of BC patients are premenopausal women, it is not clear how age at diagnosis affect the progression and outcomes of the disease considering all known prognostic factors including TNM stage, ER, PR, and HER2 status. We aim to evaluate the impact of young age on recurrence and mortality after surgery among Korean women with BC.

Methods: This is a retrospective cohort study conducted using the data from BC registry from 2000 to 2016 at Samsung Medical Cancer, Seoul, Korea. Patients who received curative BC surgery and who had histologically-confirmed invasive BC between 2000 to 2011 were included in the study. Patients who second primary cancer or double primary cancer were excluded. Information local, regional, or distant recurrence and death until May 2016 was collected using electronic medical records and National Health Statistics. Cumulative incidence rates of distant recurrence and morality at 3-years, 5-years and 10-years were calculated using a competing-risk model. Cox proportional hazards analysis were conducted with 3 different models to take into account for potential confounding factors including age, body mass index (BMI), stage and subtype at breast cancer diagnosis, chemotherapy, radiotherapy and hormone therapy.

Results:There were 7360 BC patients with curative BC surgery between 2000 and 2011, and the average follow up duration was 75.4 months. The mean age at diagnosis was 48.4 years old (Standard deviation (SD)=±10), and 6.2% (n=459) was diagnosed younger than 35. Of total, 13.3% were stage III BC and 73.4% of patients had hormone receptor positive BC. The cumulative incidence (95%CI) of recurrence at 3, 5, and 10 years was 4.4% (3.9-4.9), 7.5% (6.8-8.2), and 14.8% (12.9-16.7) respectively. The incidence of mortality at 3, 5, and 10 years was 1.8% (1.5-2.1), 3.8% (3.3-4.3), and 10.2% (9.1-11.5) respectively. Patients who were diagnosed BC under 35 years of age had 2.14 (95% confidence interval (CI):1.74-3.10) and 1.62 (95% CI:1.02-2.56) times higher risk of distant recurrence and mortality compared to patients whose age at diagnosis were between 50 to 60 after adjusting all well-known prognostic factors including stage, subtype, and BMI at diagnosis, chemotherapy, radiotherapy and hormone therapy.

Conclusions: Young age at diagnosis (<35) was the most significant predictor on BC recurrence and mortality independently from BC stage and subtype. Further study is warranted to explain biologic background for the differences in outcomes in young women with BC.

Citation Format: Kim J-Y, Cho J, Kim H, Kang D, Jung HA, Lee S-H, Bae S, Yu JH, Lee SK, Kim SW, Lee JE, Nam SJ, Ahn JS, Im Y-H, Guallar E, Park YH. Impact of young age on recurrence and mortality after surgery in breast cancer: 15 years active surveillance [abstract]. In: Proceedings of the 2016 San Antonio Breast Cancer Symposium; 2016 Dec 6-10; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2017;77(4 Suppl):Abstract nr P6-09-50.

Serum CXCR3 ligands as biomarkers for the diagnosis and treatment monitoring of tuberculosis

SETTING

Tertiary care academic medical centre.

OBJECTIVE

To evaluate the clinical utility of CXC chemokine receptor 3 (CXCR3) ligands in the diagnosis and monitoring of tuberculosis (TB).

DESIGN

Presumptive TB patients (active TB, 256; non-TB disease, 52) and 201 healthy controls were enrolled. The serum levels of interferon-gamma (IFN-γ) and CXCR3 ligands (CXCL9, a monokine induced by IFN-γ [MIG] and CXCL11, an IFN-inducible T-cell α chemoattractant [I-TAC]) were measured using enzyme-linked immunosorbent assay. An IFN-γ release assay (IGRA) was also performed. Serial samplings were performed in 19 TB patients at baseline and at 1, 2, 3, 6 and 12 months after treatment initiation.

RESULTS

All marker levels were higher in TB patients than in controls and non-TB patients. The area under the curve (AUC) for differentiating between all TB patients and controls was 0.96 (95%CI 0.94-0.98) for CXCL9, 0.84 (95%CI 0.80-0.87) for CXCL11 and 0.61 (95%CI 0.57-0.66) for IFN-γ. CXCL9 levels afforded particularly high discriminatory power between TB patients and IGRA-positive controls (AUC = 0.95, 95%CI 0.92-0.97). The levels of CXCR3 ligands decreased significantly during follow-up, and these changes were correlated with treatment response.

CONCLUSION

CXCR3 ligands CXCL9 and CXCL11 may be useful surrogate markers for the diagnosis and follow-up of TB.

Chronic periodontitis can affect the levels of potential oral cancer salivary mRNA biomarkers

BACKGROUND AND OBJECTIVE

More than 100 salivary constituents have been found to show levels significantly different in patients with oral squamous cell carcinoma (OSCC) from those found in healthy controls, and therefore have been suggested to be potential salivary biomarkers for OSCC detection. However, many of these potential OSCC salivary biomarkers are also involved in chronic inflammation, and whether the levels of these biomarkers could be affected by the presence of chronic periodontitis was not known. The objective of this pilot study was therefore to measure the levels of seven previously reported potential OSCC salivary mRNA biomarkers in patients with chronic periodontitis and compare them to levels found in patients with OSCC and healthy controls. The seven salivary mRNAs were interleukin (IL)-8, IL-1β, dual specificity phosphatase 1, H3 histone family 3A, ornithine decarboxylase antizyme 1, S100 calcium-binding protein P (S100P) and spermidine/spermine N1-acetyltransferase 1.

MATERIAL AND METHODS

Unstimulated whole saliva samples were collected from a total of 105 human subjects from the following four study groups: OSCC; CPNS (chronic periodontitis, moderate to severe degree, non-smokers); CPS (chronic periodontitis, moderate to severe degree, smokers); and healthy controls. Levels of each mRNA in patient groups (OSCC or chronic periodontitis) relative to the healthy controls were determined by a pre-amplification reverse transcription-quantitative polymerase chain reaction approach with nested gene-specific primers. Results were recorded and analyzed by the Bio-Rad CFX96 Real-Time System. Mean fold changes between each pair of patient vs. control groups were analyzed by the Mann-Whitney U-test with Bonferroni corrections.

RESULTS

Only S100P showed significantly higher levels in patients with OSCC compared to both patients with CPNS (p = 0.003) and CPS (p = 0.007). The difference in S100P levels between patients with OSCC and healthy controls was also marginally significant (p = 0.009). There was no significant difference in the levels of salivary IL-8, IL-1β and dual specificity phosphatase 1 mRNAs between patients with OSCC and patients with CPNS (p = 0.510, 0.058 and 0.078, respectively); no significant difference in levels of salivary ornithine decarboxylase antizyme 1 and spermine N1-acetyltransferase mRNAs between patients with OSCC and patients with CPS (p = 0.318 and 0.764, respectively); and no significant difference in levels of the H3 histone family 3A mRNA between patients with OSCC and either CPS (p = 0.449) or healthy controls (p = 0.107).

CONCLUSIONS

Salivary S100P mRNA could be a reliable biomarker for OSCC detection, regardless of the presence of chronic periodontitis. The presence of chronic periodontitis could significantly affect the levels of the other six mRNAs, and negatively influence reliability for using them as biomarkers for oral cancer detection.

Abstract P1-10-31: Impact of increased physical activities after diagnosis on fatigue and overall pain during cancer treatment: A prospective cohort study

Background

Existing evidence strongly suggests that exercise is not only safe but also feasible during cancer treatment. Physical activity is recommended for improving multiple post-treatment adverse effects on bone health, muscle strength, and other quality-of-life measures. Yet, limited evidence exists regarding effect of increased physical activity after diagnosis on symptoms management of breast cancer patients.

Methods

A total of 422 patients were recruited from July 2010 to July 2011 at two cancer hospitals in Seoul, Korea. Physical activity in sports (PAS) was assessed using Minnesota Leisure Time Physical Activity Questionnaire before and 2 weeks, 3-, 6-, 12-, 24- and 36-months after diagnosis. Physical symptoms including fatigue, pain, arm symptom, and insomnia were measured using EORTC-C30 and BR23. Growth mixture models were used to identify trajectory classes of physical activity patterns. Multivariate analysis was used to find impact of PAS on symptom management using SAS.

Results

Three distinct PAS groups were identified according to 3-year change patterns: moderate to moderate (MM): 40.8%, none to moderate (NM): 31.1% and moderate to high (MH): 28.1%. The LM and MH group increased PAS from diagnosis but it began to decrease from 1 year after diagnosis. Compared to the MM, the NM and MH reported significantly lower level of fatigue (MM:40.7, NM:32.2, MH:33.7), pain(MM:28.0, NM:25.6, MH:20.6), systemic therapy side effects (MM:26.9, NM:22.6, MH:21.8), and breast symptoms (MM:25.4, NM:21.7, MH:20.2) during active treatment (6 months after diagnosis).

Change patterns of quality of life according to trajectory groups At diagnosis2 weeks3 months6 months12 months24 months36 monthsFatigueMM31.3±1.930.2±1.935.3±2.0140.7±2.1137.8±2.1138.5±2.1141.0±2.21NM30.2±1.928.2±1.931.9±2.132.2±2.2233.6±2.135.6±2.2137.8±2.31MH28.8±2.327.4±2.233.0±2.433.7±2.51233.9±2.4136.2±2.5137.1±2.51PainMM15.1±1.531.3±1.9123.2±2.0128.0±2.0123.5±2.0122.0±2.0121.2±1.91NM15.4±1.532.4±2.023.3±2.0125.6±2.122.7±2.021.1±2.123.8±2.01MH17.2±1.828.4±2.3121.2±2.320.6±2.4219.7±2.321.1±2.318.6±2.2Systemic therapy side effectsMM16.8±1.114.3±1.2133.2±1.7126.9±1.5125.4±1.5126.2±1.6128.6±1.71NM15.0±1.114.5±1.235.2±1.7122.6±1.61222.0±1.6124.5±1.7127.7±1.81MH15.6±1.412.9±1.4134.4±2.0121.8±1.81221.8±1.7122.1±1.9124.7±2.01Breast symptomsMM13.8±1.226.4±1.6120.8±1.5125.4±1.6123.6±1.6119.2±1.7119.6±1.71NM13.0±1.224.7±1.6119.6±1.5121.7±1.61222.3±1.7119.9±1.8119.1±1.81MH16.0±1.424.1±1.8119.4±1.820.2±1.81217.8±1.8217.4±2.014.0±1.92*adjusted with age, stage, and radiotherapy 1 p<0.05 (differences from baseline within group), 2 p<0.05 (differences from MM group within time)

Conclusion

The results of the study confirmed that increased physical activity after diagnosis, even with patients who did not exercise at all before diagnosis, helps to control fatigue, pain, systemic side effects, and breast symptoms during treatment. It is necessary to find ways to promote physical activity after diagnosis and help patients to stay active during treatment.

Citation Format: Lee JK, Kang D, Choi E-K, Kong S, Lee S-K, Lee JE, Han W, Park YH, Ahn JS, Im YH, Noh D-Y, Nam S-J, Cho J. Impact of increased physical activities after diagnosis on fatigue and overall pain during cancer treatment: A prospective cohort study. [abstract]. In: Proceedings of the Thirty-Eighth Annual CTRC-AACR San Antonio Breast Cancer Symposium: 2015 Dec 8-12; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2016;76(4 Suppl):Abstract nr P1-10-31.

Effects of high occupational physical activity, aging, and exercise on heart rate variability among male workers

Objectives

Effects of aging and leisure time physical activity (LPA) might influence the effect of occupational physical activity (OPA) on risk for cardiovascular disease (CVD). This study was conducted to determine whether OPA affects CVD after controlling the effects of LPA and other risk factors for CVD such as job stress.

Methods

Participants were 131 male Korean manual workers. Tests for heart rate variability (HRV) were conducted for five minutes in the morning at work. We defined OPA as the combined concept of relative heart rate ratio (RHR), evaluated using a heart rate monitor.

Results

Whereas high OPA was not related to any HRV items in the younger age group, high OPA was associated with an increased number of low-value cases among all HRV items in older workers. Exercise had beneficial effects only in the younger group. After controlling for exercise and other risk factors, the odds ratios of the root-mean square of the difference of successive normal R-R intervals (rMSSD) and high frequency band power (HF) among the older age and high OPA group compared with the younger age and low OPA group were 64.0 and 18.5, respectively. Social support and shift work were independent risk factors in HRV.

Conclusions

OPA in aging workers increases CVD risks. This study provides support for the need for protection of aging workers from physical work overload, and indicates the need for further study of optimal limits of OPA.